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11:21
Cooling an Optically Trapped Ultracold Fermi Gas by Periodical Driving
Published on: March 30, 2017
Phase-slip-induced dissipation in an atomic Bose-Hubbard system
D McKay1, M White, M Pasienski
1Department of Physics, University of Illinois at Urbana-Champaign, 1110 West Green Street, Urbana, Illinois 61801, USA.
Nature
|May 3, 2008
Summary
Phase slips control dissipation in ultracold atomic Bose-Hubbard systems. This study reveals quantum tunneling and thermal activation of phase slips, clarifying their role in superfluid dissipation.
Area of Science:
- Atomic, Molecular & Optical Physics
- Condensed Matter Physics
- Quantum Gases
Background:
- Phase slips are crucial for dissipation in bosonic systems, impacting superfluidity and superconductivity.
- Understanding phase slips in small-scale superconductors is challenging due to noise and disorder.
- Previous studies often focused on high-temperature thermal fluctuations, leaving low-temperature quantum effects less clear.
Purpose of the Study:
- To investigate the role of phase slips in dissipation within a clean Bose-Hubbard system.
- To explore the low-velocity regime of ultracold atoms in an optical lattice.
- To measure the temperature dependence of dissipation strength and its underlying mechanisms.
Main Methods:
- Experimentally studying the transport of ultracold atoms trapped in a 3D optical lattice.
- Utilizing a clean and well-characterized Bose-Hubbard system to minimize uncontrolled variables.
- Measuring the damping rate of atomic motion and observing motion-induced features via time-of-flight imaging.
Main Results:
- Demonstrated that phase slips cause dissipation in the ultracold atomic Bose-Hubbard system.
- Observed a damping rate well-fitted by a model including zero-temperature damping.
- Identified a crossover from quantum tunneling of phase slips at low temperatures to thermal activation at higher temperatures.
Conclusions:
- Clarified the fundamental role of phase slips in controlling dissipation in superfluid systems.
- Provided experimental evidence for quantum tunneling and thermal activation mechanisms of phase slips.
- The Bose-Hubbard system serves as a valuable test bed for theories of bosonic dissipation and may inform understanding of phenomena in thin films.
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